Vibratory Conveyors

Electromechanical vibratory conveyors are powered by two unbalance motors which rotate in opposite directions. These types of feeders can be supplied in two types viz. trough type and tubular type depending on the type of application and material being conveyed.

Trough type conveyors
These types of electromechanical vibratory conveyors are suitable where the material conveyed is granular in nature comprising of medium / large size lumps and where fine powder content / dust is minimum. However, if required, the trough can be provided with a co-oscillating cover in order to prevent dust generated due to vibrations from escaping into the surrounding environment. In cases where the material conveyed is extremely abrasive in nature, the trough.is provided with abrasive resistant liners. These liners are fixed to the main trough by means of countersunk bolts.

Tubular Conveyors
These types of electromechanical vibratory conveyors are strongly recommended where the material conveyed has a high proportion of fines with a tendency to form dust during vibrations. A detachable lid is provided at both the ends of the tube to facilitate cleaning as and when required. Inlet and outlet nozzles with suitable flanges are provided. The inlet and outlet nozzles can be easily connected to the client's preceeding and succeeding equipment by means of flexible bellows, which also seals these points.

Advantages

• Very low maintenance required as the motors are extremely robust in construction and reliable in operation.
• Large magnitude of force can be achieved.
• Amplitude of vibrations can be varied by changing the position of the centrifugal weights in standstill condition of the motor.
• Extremely simple to connect and operate.
• Depending on the application, motors with different RPM's can be selected.

Electromagnetic Vibrating Feeders are equipped with electromagnetic drives which generate vibrations required for conveying of material. The electromagnetic drives are robust in construction with very high reliability factor. These conveyors come with a specially designed controller required for operation of the electromagnetic conveyor. These controllers convert the input AC supply voltage into pulsating DC output which results in generation of vibrations. A thyristor such as a silicon controlled rectifier is used for this purpose. The firing angle of the SCR can be varied steplessly using a potentiometer or an analogous electrical signal / PLC signal from an external command variable unit, which in turn increases / decreases the amplitude of vibrations thereby controlling the output of the conveyor as required.

As in the case of electromechanical feeders depending on the material conveyed, the conveyors can be supplied in two types viz. trough type and tubular type. Suitable liners in case of trough conveyors are provided where severely abrasive materials are handled as in the case of Electro Mechanical Conveyors.

Advantages :

• Easy and stepless variation of delivery of material either manually or automatically possible.
• Delivery remains generally constant inspite of fluctuations in supply voltage (± 10% for voltage variation & ± 3% for frequency variation.)
• Drive is extremely robust and simple in construction.
• Electromagnetic drive is dustproof and is impervious to moisture.

Isolation Of Vibrations
It is of prime importance to isolate the generated vibrations from the surroundings such as the mounting structures of the Vibrating units. This is achieved mounting the conveyor on specially designed helical springs. The spring design varies for electromechanical and electromagnetic drives. The type of spring used also depends on the rpm of the motor chosen. Depending on the requirement, the conveyors can be supplied in base mounting arrangement or suspension mounting arrangement.

Installation Of Conveyors Under A Bin
Designing of hopper / bins under which the conveyor is installed is very important in achieving the required capacity. The hopper should be designed in such a way that the conveyor tray should be relived of the material column load as far as possible. The bin outlet should be in such a way that the ratio between the depth of the bin outlet (A) and the passage height (B) should be between 0.9 to 1.25. This will facilitate easy flow of the material and help in achieving the required capacity. A typical installation is shown in the figure below.

A - DEPTH OF BIN OUTLET.
B - PASSAGE HEIGHT.
C - GAP BETWEEN BIN & FEEDER WALL.
D - HEIGHT OF TROUGH.

ORTON make Vibrating screens for grading, extracting and separation applications.

General
ORTON vibrating screens work on the principle of linear displacement of materials due to unbalance forces generated by two unbalance motors rotating in opposite direction. These screens are basically used to separate coarse materials from fine materials which exist in mixed form.

Depending on the grading size details, the number of decks required are decided. Generally the screens are provided with one deck or two decks. In case more than two decks are required for a particular application then, two vibrating screens can be used in tandem in such a way that the finest output of the first screen can be fed as the input to the second screen. The second screen will further grade and separate the material as required.

The selection ..of the screen deck mesh will depend on factors such as the material to be screened, whether the material is dry and free flowing or is moist and sticky, particle size of the material to be screened, shape of the material etc. Utmost care is to be taken to ensure that the screen decks do not get clogged as this will result in reduced screening area thereby affecting the output of the screen.

The screen body is extremely sturdy and rugged made up of mild steel of adequate thickness. The thickness of the steel plates depends upon the size of the screen and the selected motor.

Depending on the material to be screened, the sieve analysis and other related factors, suitable screen decks are provided. Normally these decks are in the form of wire mesh or perforated plates.

The screens are mounted on the structural framework via specially designed mounting springs. The selection of these springs will depend on the total weight of the equipment and the motor rpm. These screens are usually base mounted, however they can also be suspended if the situation demands.

The screens are provided with suitable inlet and outlet openings as required by the customer. The positioning of the outlets will depend upon the requirement of the customer.

Few typical applications of screens are shown below

Type	Application
Screens in cascade	Separation of mixture of coarse, medium and fine to very fine particles of material (e.g. Sand)
Screens for material grading	Grading of oversize and undersize material (eg. Minerals, Coal, Gravel)
Screens for Extracting	Extracting of very coarse materials from fine material (eg. Scraping, Coal, Ballast)
Shakeouts Screens	Segreating sand from casting

The above illustrations are indicative only

Standard supply voltage required for the motor is 415 V, 3 Ph, 50 Hz. The motors can be started through a DOL starter circuit. The panel can be supplied if required by the client.

In order to avoid resonant elliptical oscillations (amplitude of which are extremely high during stopping), A D.C. braking circuit can be incorporated which will neutralize the inertial effect of the motors, thereby stopping the motors instantaneously. This is .an optional feature and is generally recommended for bigger size motors used in conveyers and screens.